There was no reason to expect much from Cinderella Man, Ron Howard's biography of boxer James Braddock, who in the summer of 1935 became the most unlikely heavyweight champion in the history of boxing. After all, it's a true tale whose outcome has been predetermined; surely there could be no tension in its telling, no shock at its finale when David bests the Goliath who wore a Star of David on his flashy silk trunks.

Howard, like Braddock in the late 1920s, has provided occasional glimpses of finesse -- Apollo 13 and A Beautiful Mind, also true stories -- but too often his footwork was too slow, his jabs too pedestrian to merit the appellation of Great Director, to which anyone who's sat, or slept, through The Missing and EDtv or How the Grinch Stole Christmas or Backdraft can attest. There was never any reason to believe he had a masterpiece in him, something that would dash his reputation as a mild-mannered maker of mild-tasting movies that go down easy and still leave you feeling empty.

Cinderella Man is, at last, his first great (and filling) movie -- inspirational, yes, but far from hokey; moving, absolutely, but never saccharine; and gripping, despite its being a fixed fight about a decent man who, in the span of nine months, went from welfare recipient to snatching the champion's belt from Max Baer, who swore he might kill Jim Braddock in the ring. Appropriately, given its subject is a man who was too proud to take a dive for easy money even when he was being used as "meat" by promoters who thought him washed-up, it exhibits a swagger heretofore absent from Howard's work. It vibrates with the kinetic energy Martin Scorsese used to bring to the office, and though only the cynic would dismiss it as Raging Bull with a happy ending, Cinderella Man does serve as its heartening opposite. It will make you feel good, the function of all of Howard's films, but not before it tries to break you just a little.

It does not bode well when the movie opens with a quote from writer Damon Runyon, who provided Braddock, played in the film by Russell Crowe, with the nickname "Cinderella Man." (The half-dozen books written about the fighter, including Jeremy Schaap's new Cinderella Man: James Braddock, Max Baer, and the Greatest Upset in Boxing History, use the phrase somewhere in their titles.) The epigraph insists that "there is no more interesting story" in all of sports than that of Braddock, which one initially reads as a warning: This is going to be a very long movie, but, seriously, it's worth it. (At almost two and a half hours, Cinderella Man still feels half as long as Star Wars Episode III: Revenge of the Sith.) But Howard rushes forward, wasting not a second of its running time, dropping us in the ring on November 30, 1928, when Braddock knocked out "Tuffy" Griffiths in the second round and pocketed some $15,000. These are happy moments for Braddock: He's in line for a title fight, making good money and living in New Jersey middle-class comfort with wife Mae (a stoically understated Renée Zellweger) and their three kids. But the good times do not last long.

In a brilliantly edited sequence in which a mansion crumbles into a heaping hovel and a champ takes on the look of a battered chump, the year is 1933, and James Braddock is broke and broken -- a would-be champ who, in five years, lost all his money, the use of his right hand and some of his teeth. His career went the way of the nation during the Depression; he's stripped of his license to fight, and his manager, Joe Gould (Paul Giamatti), is forced to abandon his friend. Braddock begs for work in the shipping yards and befriends a man (In America'sPaddy Considine) who, in time, will find himself a pitiable resident of Hooverville, the squalid, outlaw homeless camp in Central Park. (The depiction of Depression-era New York and New Jersey recalls the work of John Sayles or latter-day Scorsese, yet without the proselytizing of the former or the compulsiveness of the latter.) In one of the film's most moving sequences, Braddock owes so much and has so little, he's forced to pass the hat among the boxing commissioners and promoters who once made so much off of him.

Howard and writers Akiva Goldsman and Cliff Hollingsworth squeeze every drop of sweat from their story; its inevitable happy ending is hard earned, though unfortunately it makes Baer (Craig Bierko, finally living up to his potential) too much a villain and Braddock so much a saint. Theirs is as much a movie about boxing-film genre clichés as Raging Bull was -- brutality depicted as a thing of beauty, the spilling of blood equated with the showing of heart, redemption as a thing claimed by beating another man to pulp. But rather than merely, desperately reproducing "the mechanical quality [the clichés] once had" and sucking the fun out of the formula, as Pauline Kael wrote in her scathing review of Scorsese's film, the old-fashioned Howard revels in the conventions, to the point where he doesn't so much reinvent them as much as he reinvigorates them. Who knew Opie was a contender after all?